Means for grounding metal covers on electrical devices



June 29, 1954 H. HUBBELL 2,682,646

MEANS FOR GEOUNDING METAL COVERS oN ELECTRICAL DEVICES A Filed Feb. 21, 195o M Gttorneg Patented `lune 269, 1954 UNITED STATE MEANS FOR GRUNDING METAL COVERS ELECTRICAL DEVICES Harvey Hubbell, Long Hill, Conn.

, Application February 21, 1950,- Serial No. 145,355

. 1 This invention relates to ground connecting devices foi` electrical connectors and the like, and particularly to the ground connection between the metal cover of an electrical connector and the grounding contact of such connector. Connectors of the type here involved are frequently employed, for example, in connecting a three conductor cable to some current consuming unit, or in connecting different cable sections together, and other similar purposes.

An object of this invention is to provide a ground connection for use on electrical connectors `constructed and" arranged to be entirely selfcontained within the connector and to require no extraneous parts or elements on the outside thereof. l l

In oneof its more specific aspects, the invention is adapted for use in two parts electrical receptacles in which the different portions of the receptacle body are separated for connection `to a three conductor cable, for example, and :and thereafter reassembled and secured together. A further object is to provide an improved ground connecting device forr electrical receptacles of this type constructed and arranged to automatically complete the ground connection upon assembling and securing the diil'erent portions of the receptacle together, thus avoiding all necessity for any other operation which might be neglected by a user.

` A still further object is to provide a ground connection for two part electrical devices in which the separate parts can be joined together only in the correct manner` to complete the desired ground connection.

With the foregoing and other objects in view, I have devised the constructionillustrated in the accompanying drawing forming a part of this specification. It is, however, to be understood the invention is not limited to the specic details of construction and arrangement shown, but may embody various changes and modications within the scope of the invention.

` In this drawing:

Fig. 1 is a plan View of the outer end of the receptacle element of a connector embodying the present invention;

Fig. 2 is` a section through the plug to be used with the receptacle shown in Fig. 1;

7 Claims. (Cl. 339-14) 2 ceptacle section shown in Fig. 3 assembled with the other section of this receptacle;

Fig. 5 is a section through a part of the receptacle section shown in Fig. 3, taken on the line 5-5 thereof;

Fig. 6 is a view partly in section through the grounding connection between the two portions of the receptacle shown in Fig. 4, and

Fig. '7 is an end View from the bottom of Fig. 4, an associated three conductor cable being in section.

The illustrated embodiment of the invention is shown as forming part of an electrical receptacle adapted to cooperate with a plug connector in connecting together two sections I I, I2 of a three conductor cable, for example, having two live conductors and a grounded neutral conductor. As shown in Fig. 2, a cooperating plug connection I3 has two contact blades I4, I5 connected to the two live conductors I6, I'I of the cable section I I and a U-shaped neutral contact blade IS mounted on metal base plate |8105 connected to the neutral conductor I9, all by conventional binding screws 2|.

The specific adaptation of the invention illustrated is shown as part of an electrical receptacle 22 having two separable body sections 23, 24 of insulating material adapted to be secured t0- gether and to cooperate with the plug connector I3 in connecting, for example, the two cable portions II, I2. One section 24 is formed to be connected to the cable portion I2 and has a metal cover 25. A pair o f clamping jaws 26, 27 having flanges 2B, 29, slidable in oppositely disposed radial grooves 3l in the cover are arranged to clamp the cover 25 to the sheath or metal cover 32 of the BX cable portion I2 by means of clamping screws 33, thus providing a ground connection between the receptacle cover 25 and the cable sheath 32. The body section 24 is annular and has a central opening 33 to receive the end of the I3 for connecting the two portions of the cable together. Two such contacts Sli, 35 located in compartments 31m with entrance slots 34h leading to them for the plug contacts Ill and I5, are connected to the two live conductors 36, 3l of the cable portion I2 by binding screws 38, 39 and a neutral grounding contact III is connected to the neutral or ground conductor 42 by a binding screw 43. Contact 4I is located in a compartment 56 with an opening 51 leading to it for entrance of ground contact i8 to engage contact lll, the opening 51 being of the general shape of contact I8. Contact lll is mounted on the base plate,` 58 into which the binding screw 43 is threaded.

In order to provide a ground connection between the neutral grounding contact 4l and the metal cover 25, and through it to the sheath or cover 32 of the cable, the illustrated embodiment provides a shunt connection formedv by a conducting strap 114 riveted at one end to the contact all and extending through a slot 4 in the body section 23 into a recess tl where it is shaped to form a spring arm Il? siidably engaging one of the securing screws fill employed in securing the two body sections 23, 24 together, there being three such screws t8, lila and 4319, spaced around the edge of the body section 23. Screws 43a and 68h are adapted to thread into sockets, not shown, inserted in the body section 24. The grounding screw 48 is adapted to thread into a socket 5| embedded in the body section Ztl and having its opposite end 52 electrically connected by riveting or otherwise to the metal. cover 25, thus completing a grounding connection between the grounding contactlll and the metal cover 25.

Means is provided to prevent the two body sections 23, 2d from being assembled in any other position than the right one to insure the `ground connection being completed by the act f of connecting the two sections together. As shown, the inner end 52a of the socket member 5I projects beyond the section 24 and is formed with a cross section different from that of the other sockets whichreceive the other securing screws 23a and fliib, being preferably square as shown. The body section 23 has a recess 53 of similar square cross section in which only the socket 5i can be inserted. As shown in Figs. 4 and 6, the recess 53 is provided in a cover plate 55 of insulating material forming a cover for the inner end of the body section and the contact chambers therein.

In operati.o`n,'the three conductors of the cable portion l2 are connected to the respective contacts in the body section 23 after being inserted through the opening 33 in the section i245, care being employed to connect the neutral conductor #il to the neutral or grounding connector 4I.

For this purpose the binding screw for exi ample, may have a distinctive color to indicate the proper connection for the neutral conductor d2. Thereupon, when the two sections of the receptacle 22 are brought together, the characteristic cross section on the projecting end of the socket member 5i and the recess 53 prevent the tivo sections being assembled in any but the right position to automatically complete the ground connection between the grounding connector 4l and the metal cover E5.

The invention provides an improved ground connection between the metal cover 25 and the grounding contact ill, all the parts of which are entirely housed within the receptacle 22, no parts being required on the outside. When the two sections 'are connected together, tightening of the conventional connecting screws automatically completes the ground connection, and no additional operation, such as might be neglected by the user, is required.

Having thus set forth the nature of my invention, I claim:

l 1. An electrical receptacle comprising two body sections o'f insulating material, a metal cover for one section, said latter section being provided with a compartment open on one side toward the other section and an opening through the opposite side leading to said compartment to receive a conductor cable, the other section being provided with a series of compartments opening through its inner end toward the compartment in the first section, and contact entrance slots leading to 'said compartments in its outer end wall, receptacle contacts in the latter compartments including a grounding contact, an insulating cover plate over said compartments to retain the contacts therein, means for connecting the conductors of a cable extending into the ycompartment. of the iirst section to the respective contacts, and current conducting means securing said body sections together comprising a pair of cooperating threaded members one of which yis mounted in the first body section and connected to the cover and the other mounted in the second body section and electrically connectecl with the grounding contact.

2. An electric receptacle comprising a pair of sections of insulating material, one section having a metal cover and being arranged to receive a conductor cable, receptacle contact members in the other section including a grounding contact,

means for connecting the conductors ci a cable extending into said first section to the respective contacts, and "current conducting means connecting said sections together inclu-ding cooperating securing members mounted one in each section, said member in one section being electrically connected to said cover and the member in the other section electrically connected to said grounding contact, whereby joining said sections together electrically connects said grounding contact to said cover.

3. An electric receptacle comprising a body section of insulating material, a metal cover for said section, means adapted to electrically and mechanically connect said cover to the sheath of an associated cable, a second body section of insulating material, a plurality of receptacle contacts mounted therein, securing means in said body sections connecting said body sections together, the connecting means in the second section electrically connected to one of said contacts and the securing means in the other section electrically connected to said cover to form a ground connection between said contact and said cover, sai-d securing means including a threaded socket member in one section connected to said metal cover and a .threaded fastening meansin said other section electrically connected to one of said contacts and engaging said socket member to join said body sections together.

4. An electric receptacle comprising a body section of insulating material, a metal cover for said section, a second body section, a plurality of receptacle contacts mounted in said latter section, and securing means connecting said body sections together' electrically connected to one of said contacts and to said cover to form a ground connection between said contact and said cover, said securing means including a threaded socket member of non-circular cross-section in said first body section electrically connected to said metal cover and seated in a recess' of similar cross 'section in 'said other body section, and a. threaded fastening means in said other section engaging said vsocket member 'to join said body sections together.

5. An electric receptacle comprising 'a ybody section of insulating material, a metal cover for said section, a second body section, a grounding contact mounted in the second section and an insulating cover plate on the inner end of said section, and securing means connecting said body sections together electrically connected to said grounding contact and to said metal cover to form a ground connection between said contact and said cover, said securing means including a threaded socket member of noncircular cross sec tion extending through said first body section and connected at one end to said metal cover and projecting at the other end to provide a projection of noncircular cross section seated in a recess of similar cross section in said cover plate, and a threaded fastening means in said other section electrically connected to said contact and engaging said socket member to join said body sections together.

6. An electric receptacle comprising a body section of insulating material and a metal cover therefor, a second body section of insulating material, a grounding contact and an insulating cover plate mounted on the latter section, and securing means connecting said body sections together electrically connected to said grounding contact and to said metal cover to form a ground connection between said contact and said cover, said securing means including a threaded socket member of noncircular cross section extending through said first body section and connected at one end to said metal cover and projecting at the other end to provide a. projection of noncircular cross section seated in a recess of similar cross section in said cover plate, and a threaded fastening means in said other section engaged in said socket member to join said body sections together, and a current conducting strap secured to said contact slidably engaging said threaded fastening means to provide a shunt connection therebetween, whereby said grounding contact and said metal cover are electrically connected.

7. An electric receptacle comprising a body section of insulating material and a metal cover therefor, a second body section of insulating material, a grounding contact and an insulating cover plate mounted on the latter section, and securing means connecting said body sections together electrically connected to said grounding -contact and to said metal cover to form a ground connection between said contact and said cover, said securing means including a, threaded socket member of noncircular cross section extending through said rst body section and connected at one end to said metal cover and projecting at the other end to provide a projection of noncircular cross section seated in a recess of similar cross section in said cover plate, and a threaded fastening means in said other section engaged in said socket member to join said body sections together, and a current conducting strap secured to said contact having a spring arm slidably engaging said threaded fastening means to provide a shunt connection therebetween, whereby said grounding contact and said metal cover are electrically connected.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,782,527 Bennett Nov. 25, 1930 1,891,153 Gates Dec. 13, 1932 1,954,375 Blinn Apr. 10, 1934 1,967,091 Kempton July 17, 1934 2,032,501 Reynolds Mar. 3, 1936 2,410,618 Zelov Nov. 5, 1946 

